The Padres and Cardinals have completed a trade that sends shortstop Khalil Greene to St. Louis.

The Padres agreed to the deal Wednesday, and San Diego General Manager Kevin Towers announced it tonight.

The Padres will receive relief pitcher Mark Worrell, a 25-year-old right-hander who was 3-3 with a 2.15 ERA last season in Triple A. He has averaged more than a strikeout per inning and had 80 strikeouts in 58 2/3 innings last season in the Pacific Coast League.

The Padres will receive another player to be determined later, off a list of three Cardinals minor leaguers. Two of those on the list are pitchers.

Worrell has 84 saves in his minor league career. He was drafted by St. Louis in the 12th round in 2004 out of Florida International.

Worrell – who is not related to former major league pitchers Tim and Todd Worrell – appeared in four major league games for the Cardinals in 2008, compiling a 7.94 ERA and 0-1 record in 5 2/3 innings. At the plate, he fared better: in two at-bats with St. Louis, he had one hit – a three-run home run.

But this trade is primarily about moving Greene's $6.5 million salary in anticipation of a much smaller payroll in 2009. The deal may not be announced until later Thursday or Friday.

The move could improve the club's chances of retaining ace pitcher Jake Peavy or gaining leverage in trade talks involving Peavy, who is guaranteed $11 million next year and $63 million over the next four years.

The club has shopped Peavy for three months without finding a deal. Braves shortstop Yunel Escobar was part of the talks involving Peavy, but as of Tuesday the Padres and Braves had not revisited those talks.

The Padres have made progress in talks with the Cubs, setting up a 5-for-1 trade, but Chicago is awaiting results of an ownership bid and also has concerns about fitting Peavy's salary into its 2009 payroll. Peavy's consent is needed for a trade, and persons close to him say he is more inclined to approve a trade to the Cubs than the Braves.

Greene, 28, has been the Padres' primary shortstop since 2004. A first-round draft pick of the Padres in 2002, he batted .213 with 10 home runs and 100 strikeouts last season, one year after hitting 27 home runs and 44 doubles.

His frustration over a season-long hitting slump boiled over July 30, when Greene swiped a storage chest in a clubhouse tunnel at Petco Park, fracturing his left hand. He missed the final two months of 2008 because of the injury.

In response to the self-inflicted fracture, the Padres stopped paying Greene's salary in August. The players union intervened on Greene's behalf, and the Padres paid back Greene's salary, but in an attempt to recoup up to $1.47 million from Greene, the club filed a grievance that has yet to be heard and may now be dropped.

Greene, who can be a free agent next November, turned down a four-year, $29-million offer from the Padres last offseason. Uncertainty over whether the club could retain him after the 2009 season factored into the club's decision to shop Greene, General Manager Kevin Towers said last month.

Utility man Luis Rodriguez replaced Greene last season, but the Padres may look to find a full-time shortstop to replace Greene.

Towers said Thursday night the club's best option may be to trade for a shortstop.

"There are some people we have identified as free agents who could be potential guys at the position," Towers said. "We don't have a lot of wherewithal to spend a lot of money on a free agent. So our best option probably is going to be to trade for one."